The Access ESP system, a Thru Tubing Conveyed Electrical Submersible Pump (TTCESP), also referred to as a rigless ESP system, was installed in a well that had a history of producing significant amounts of sand and fine solids. During production of the wellbore fluids, solids accumulate in the well bore and lower completion restricting the inflow and well performance below the ESP, requiring a clean out intervention with a coiled-tubing operation to clear the restriction and return the well to full performance.
This paper records the retrieval and replacement of the rigless ESP to access the wellbore and perform a coiled-tubing clean out of the lower completion wellbore without the use of a heavy workover rig. The rigless ESP retrievable assembly components were removed through tubing, in a live well intervention, using a slickline unit, and coiled tubing unit. The application of the AccessESP system provided significant benefits and demonstrated its potential application for any ESP operation that necessitates frequent well interventions, has high rig costs, or resides in locations with limited rig availability.
The rigless ESP retrievable assembly is made up of four segments that are retrieved individually. Beginning from the uphole end of the retrievable ESP assembly, the first segment is the tubing stop, next a tubing packoff with a standing valve, then the complete pump assembly from pump discharge, pump, and pump intake, and on the downhole end is the motor assembly which includes the seals, motor, downhole gauge, and plugarm wet connector assembly. When these four components of the retrievable ESP assembly have been pulled from the well thru-tubing, there is open access to the lower completion wellbore.
An isolation sleeve was installed to protect the wet connector dock in the rigless ESP permanent completion from mechanical damage during the coil-tubing clean out process. After the clean out was completed the isolation sleeve was retrieved and the four components of the rigless ESP assembly were reinstalled and the well was placed back on production. The intervention and methods described herein confirms the viability of the access to the lower completion and wellbore and to perform slickline and coiled tubing well work interventions with the rigless ESP system.